Why is my video playing limited to a couple seconds when i add it to VSE?
I'd be willing to bet that you need to set the frame range. The length of your video is pretty close to 250 frames, which is the default.

Check out #2.



The length of the video is also controlled by frame RATE. Make sure this is set to the same frame rate as the original video.

Check out "Frame Rate" set to 24fps below.